Santoku automagically scales recipes up and down, or if you've got limited quantities of an important ingredient, you can scale the entire recipe to that ingredient. Just type your recipe in to try it!
"Scaling recipes is a pain, but I only ever double/triple/halve recipes, and that's easy to calculate."
That's what I said, until I had a recipe that called for three cups of cream but I only had 1-1/4 cups. And then wrote this app instead of doing the arithmetic.